diff --git a/services/core/java/com/android/server/wm/RootWindowContainer.java b/services/core/java/com/android/server/wm/RootWindowContainer.java
index 14316fa681361..eaf76938e2e83 100644
--- a/services/core/java/com/android/server/wm/RootWindowContainer.java
+++ b/services/core/java/com/android/server/wm/RootWindowContainer.java
@@ -3262,7 +3262,7 @@ class RootWindowContainer extends WindowContainer<DisplayContent>
             int numTaskContainers = display.getTaskDisplayAreaCount();
             for (int tdaNdx = 0; tdaNdx < numTaskContainers; tdaNdx++) {
                 final TaskDisplayArea taskDisplayArea = display.getTaskDisplayAreaAt(tdaNdx);
-                final int numStacks = display.getStackCount();
+                final int numStacks = taskDisplayArea.getStackCount();
                 for (int stackNdx = 0; stackNdx < numStacks; ++stackNdx) {
                     final ActivityStack stack = taskDisplayArea.getStackAt(stackNdx);
                     stack.finishVoiceTask(session);